The present invention relates to an image drawing method and an image drawing apparatus. Further, the present invention relates to a recording medium which stores a program for carrying out image processing, and the program itself.
In recent years, there has been a rapid advancement of computer graphics techniques, such as hidden line removal, hidden surface removal, smooth shading, and texture mapping thanks to the dramatic development of hardware.
Generally, with computer graphics techniques, images are generated by the following procedure. Firstly, a plurality of three-dimensional objects are generated by three-dimensional modeling. Then, rendering is performed by adding optical properties such as specular reflection, diffuse reflection, refraction, and transparency to the objects using shading techniques, by adding surface patterns to the objects, and by plotting images depending on surroundings, such as a window and scenery reflections and ambient light.
According to a conventional method, the movement of fluid, such as flowing water or flowing smoke, can be drawn by randomly moving many objects, and thereafter mapping a texture image of water or smoke on each of the objects.
In rendering a polygon, generally, a perspective transformation is performed for each vertex of the polygon by a geometry processor and the transformed polygon is drawn by a drawing processor in an image memory for displaying images.
For example, it is assumed that “n” objects are randomly moved, and thereafter, a texture image is mapped on each of the objects. In this example, the above described process for rendering a polygon needs to be performed for each of the “n” objects. That is, the perspective transformation needs to be performed “n” times for each vertex of the polygons, and the drawing operation needs to be performed “n” times for each of the polygons.
Since many objects are required to make the flowing water or flowing smoke realistic, considerable time and complicated calculations are needed for the above rendering process. As a result, the objects are displayed at a slow speed on a monitor.